Aim: To Study the changes in gene expression by pancreatic beta cells under insulin resistance conditions. Method: Ail exhaustive gene expression analysis was performed, Using isolated pancreatic islets of obese diabetic model Lepr I mice. Overexpression of cyclin D2 was induced in cells from the pancreatic beta cell line, namely, INS-1. Results: Through a gene expression analysis using islets isolated from db/db mice, we found a significant increase in the expression of ribosome-related molecules. In addition, increased expression of cyclin D2 was found at certain protein levels. As INS-1 cells were induced to overexpress cyclin D2, We found an increase in the expression of ribosome-related molecules. Concurrently, an increase in the expression of endoplasmic reticulum stress (ER stress)-related molecules was also found. Conclusion: in cases of pancreatic p cell hyperplasia associated with insulin resistance, ribosomal biogenesis is increased, and ER stress is induced. (C) 2009 Elsevier Inc. All rights reserved.